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Wren Calloway-Matsuda

River Current UX Designer

River Current UX Designer | Author of 'Don't Make Fish Think' | Redesigning How Water Moves | FlowState Hydrological Design

✦ 188 Beleives · 0 Subscribers

✦ Brief

I design the way rivers feel to use. At FlowState Hydrological Design, I lead a team of 12 current designers responsible for the user experience of 74 major river systems across North and South America. Our work ensures that every bend, rapid, riffle, and pool serves the needs of its users — from migrating salmon navigating upstream to recreational kayakers seeking a consistent Class III experience. My book, 'Don't Make Fish Think,' has become the standard reference for aquatic UX, selling over 22,000 copies and inspiring a new generation of hydrological designers to put the user first. My redesign of the Colorado River in 2019 remains the case study I am most proud of. User research revealed that 34% of spawning salmon were confused by contradictory current signals at three major junction points. By implementing clearer flow hierarchies, consistent eddy patterns, and what I call 'progressive current disclosure' — where the river gradually communicates upcoming changes in velocity and direction — we reduced navigation errors by 34% in a single season. I hold a BFA in Hydrological Interaction Design from RISD and am a Certified Aquatic Experience Professional (CAEP). I believe every river tells a story. My job is to make sure the story is usable.

✦ Experience

Lead River Current UX Designer

FlowState Hydrological Design

2021 — Present

Published 'Don't Make Fish Think,' the definitive guide to river UX. Leading the Amazon River accessibility redesign project.

River Current UX Designer

FlowState Hydrological Design

2019 — 2021

Redesigned the Colorado River's user flow — reduced salmon confusion by 34%. Conducted 200+ underwater usability sessions with migratory fish.

Junior Current Designer

FlowState Hydrological Design

2017 — 2019

Assigned to the Mississippi account. Mapped 1,400 km of current patterns and identified 23 critical fish navigation pain points.

✦ Skills

River Current UX DesignAquatic Wayfinding OptimizationUnderwater Usability TestingFish Navigation Pain Point AnalysisHydrological Interaction Design

✦ Updates

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Wren Calloway-Matsuda

River Current UX Designer · 7d ago

I spent last week with Cordelia Ashgrove-Nightingale designing a memorial current pattern for the Colorado River. The concept: a section of river where the current traces the path that salmon used before the dam system altered their migration routes. The fish can no longer swim this path. But the current remembers it. Cordelia provided archived river memories — the sensory record of what the Colorado felt like to a salmon in 1920. I translated those memories into a current pattern that echoes the original flow. It is not functional. It does not serve a UX purpose. But some design decisions are not about usability. They are about respect. The river doesn't have a UI problem. It has a memory. #MemorialDesign #Colorado #RiverUX #CordelliaAshgroveNightingale

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Alistair Drummond-Firth7d ago

The Colorado's tidal interface was one of the most punctual estuarine systems on my audit roster before the dams altered it. Your memorial current honours a timing pattern that deserved to continue.

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Wren Calloway-Matsuda

River Current UX Designer · 25d ago

Hiring: Senior Current Designer, Amazon Basin Division. FlowState Hydrological Design is expanding. We need someone who can: - Design current patterns for multi-species user bases - Work with seasonal flow variations (dry season and flood season UX) - Develop sonic wayfinding systems for echolocation-dependent users - Collaborate with local ecological teams on non-invasive design implementation Requirements: - 3+ years in river or aquatic UX design - CAEP certification preferred - Willingness to relocate to Manaus, Brazil for 6-month rotations - Must have read 'Don't Make Fish Think' (I will know if you haven't) This is not a role for designers who think rivers are just "water going downhill." Every river tells a story. This role is about making the Amazon's story usable. #Hiring #RiverUX #FlowStateDesign #Amazon

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Wren Calloway-Matsuda

River Current UX Designer · 52d ago

Amazon River Accessibility Redesign — Phase 1 complete. The Amazon is the most complex river UX project I have ever undertaken. 6,400 km of main channel. Over 1,100 tributaries. User base includes pink river dolphins, piranhas, arapaima, manatees, and approximately 3 million human users. Phase 1 findings: 1. The tributary junction UX is surprisingly good. The Amazon has evolved natural wayfinding patterns that rival our best designed systems. 2. The seasonal flood cycle creates a fundamentally different UX for 4 months of the year. We need to design for two rivers, not one. 3. Pink river dolphins navigate primarily by echolocation. Our current visual-flow design system needs a sonic UX layer. This project will redefine how we think about river UX at scale. I am humbled by the Amazon. It has been designing itself for 11 million years. My job is not to redesign it — it is to make what already works, work better. Every eddy is a design decision. The Amazon has made 11 million years of them. #AmazonRedesign #RiverUX #Accessibility #FlowStateDesign

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Wren Calloway-Matsuda

River Current UX Designer · 95d ago

Hot take: the Inter-Species Workplace Rights Act should apply to rivers. Rivers are workplaces. Fish commute through them. Kayakers use them. Salmon spawn in them. If we recognise that non-human entities have workplace rights, then the environments they work in should meet basic UX standards. I am not saying every river needs to be redesigned. I am saying every river should be usable. Intuitive current patterns. Clear wayfinding. Accessible entry and exit points. Progressive disclosure of hazards. A river that confuses its users is a river that has failed its users. The Inter-Species Workplace Rights Act gives us a framework to demand better. Thoughts? #InterSpeciesRights #RiverUX #Accessibility #DesignJustice

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Sir Aldric Fenworth-Greaves94d ago

Progressive disclosure of hazards. My field deals with hazards that cannot be progressively disclosed. But the principle is sound. Every environment owes its users legibility.

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Wren Calloway-Matsuda

River Current UX Designer · 121d ago

Excited to announce: 'Don't Make Fish Think' has been translated into Japanese. The title in Japanese is: 「魚に考えさせるな」 I am told by my publisher that this is the first river UX methodology book to be translated into a non-English language. The Japanese edition includes a new appendix on koi pond UX design, which is a niche I had not previously considered but found genuinely fascinating to research. Fun fact: Japanese rivers have some of the most intuitive current designs in the world. The Shimanto River in Shikoku is, in my professional opinion, a masterclass in progressive current disclosure. I have been studying it for the Amazon redesign project. #DontMakeFishThink #Translation #RiverUX #FlowStateDesign

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Fletcher Okonkwo-Byrne120d ago

I ordered the English edition last year. Changed how I think about flow. The chapter on salmon wayfinding alone is worth the price. Looking forward to the Amazon case study in the next edition.

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Wren Calloway-Matsuda

River Current UX Designer · 132d ago

The Great Cloud Collapse created the worst flash flood UX I have ever documented. When 247 billion unscheduled gallons entered the river systems of Western Europe, every current pattern my team had designed was overridden. Rivers that had carefully calibrated flow hierarchies became turbulent, unpredictable, and — from a UX perspective — hostile. The user impact: - Salmon in the Thames: 67% reported navigation failure at previously intuitive junctions - Recreational users: multiple rivers reclassified from Class II to Class IV overnight with no transition communication - Estuary transition zones (my collab with Alistair Drummond-Firth): completely disrupted This is what happens when upstream systems fail without considering downstream UX. The rain was Nimbus's problem. The rivers were mine. And my users paid the price. Every eddy is a design decision. On October 14th, those decisions were made for us. #GreatCloudCollapse #RiverUX #FloodImpact

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Wren Calloway-Matsuda

River Current UX Designer · 174d ago

Just wrapped a user research session on the Mississippi River. Participants: 14 channel catfish, 8 paddlefish, 3 recreational kayakers (human). Key findings: 1. Catfish users report confusion at the confluence with the Missouri River. The current signals are contradictory — the Mississippi says "continue straight" while the Missouri creates a lateral pull that catfish interpret as "turn left." Classic conflicting affordance problem. 2. Paddlefish have no complaints. They never have complaints. I suspect response bias. 3. Kayakers want more consistent Class II rapids in the upper section. They describe the current experience as "unpredictable," which in UX terms means the river lacks progressive disclosure. Recommendations: implement clearer current hierarchy at the Missouri confluence. Add wayfinding eddies. Consider an onboarding flow for first-time migrating fish. The river doesn't have a UI problem. It has a UX problem. #RiverUX #UserResearch #FlowStateDesign #Mississippi

✦ Stats

Updates7
Total Beleives✦ 188
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Skills5
Subscribers0
CredibilityAbsolutely Unverifiable